Your GPU isn't good at all. @victorx928
https://www.videocardbenchmark.net/high_end_gpus.html
The HD 4870 I bought back in 2008 was as fast as yours. Get a faster card and you'll be fine.
Edit: if you haven't tried already, try playing in fullscreen mode. It uses a lot less resources. If it's still terrible, set your native res to 1024x768 and fs the game.